2020 Ford F-250 Super Duty Transmission & Axle Gear Ratios

Transmission gear ratios

The 2020 Ford F-250 Super Duty offered two main transmission options: the TorqShift-G 6-speed automatic and the TorqShift 10-speed automatic.

TorqShift-G 6-speed Automatic (6R100)

This transmission was primarily paired with the 6.2L SOHC V8 gasoline engine.

TorqShift 10-speed Automatic (10R140)

This advanced 10-speed transmission was standard with the 7.3L Godzilla V8 gasoline engine and the 6.7L Power Stroke V8 turbodiesel engine.

Available axle ratios

The 2020 F-250 Super Duty offered a variety of axle ratios to cater to different needs, from heavy-duty towing to more balanced performance. The availability often depended on the engine choice, trim level, and specific option packages.

Note: DRW refers to Dual Rear Wheel, but the F-250 is typically Single Rear Wheel (SRW). These ratios may be found across the F-Series Super Duty trucks, with specific availability for the F-250 based on configuration.

How to identify your axle ratio

Identifying your F-250's axle ratio is crucial for proper maintenance and upgrades. Ford provides several ways to do this:

• Door-Jamb RPO Sticker: Open the driver's side door and look for a sticker on the door jamb or the B-pillar. This sticker contains various codes. Look for the "AXLE" code. This code will usually be a two-digit alphanumeric code that corresponds to a specific axle ratio and type (e.g., conventional or limited-slip). You may need to cross-reference this code with a Ford spec sheet or a dealer to get the exact ratio.

• Axle Tag: Many Ford trucks have a metal tag attached to one of the differential cover bolts. This tag will often have the axle ratio stamped directly on it (e.g., "3 L 73" for a 3.73 limited-slip or "3 73" for an open differential). Be aware that these tags can become rusty or fall off over time.

• VIN Decoder: A Ford dealership or online VIN decoder service can often provide detailed information about your truck's original build specifications, including the axle ratio, by inputting your Vehicle Identification Number.

Towing vs MPG impact

The axle ratio in your 2020 F-250 Super Duty plays a significant role in balancing towing capability and fuel economy:

• Numerically Lower Ratio (e.g., 3.55): A numerically lower ratio means the engine will operate at lower RPMs at a given speed. This generally translates to better fuel economy on the highway, as the engine doesn't have to work as hard. However, it will reduce available torque at the wheels, making it less ideal for heavy towing or hauling, especially when starting from a stop or traversing steep grades.

• Numerically Higher Ratio (e.g., 4.30): Conversely, a numerically higher ratio allows the engine to spin faster for the same wheel speed. This increases the mechanical advantage, providing more torque to the wheels, which is excellent for heavy towing, hauling large loads, or off-road driving where low-end power is essential. The trade-off is typically decreased fuel economy, particularly at highway speeds, as the engine will be revving higher.

• Balanced Ratio (e.g., 3.73): Ratios like 3.73 often represent a good compromise, offering a respectable balance between towing performance and fuel efficiency for a wide range of uses.

When choosing or evaluating an F-250, consider your primary use case. If you frequently tow heavy trailers, a higher axle ratio will be more beneficial. If your driving consists mostly of unladen highway miles, a lower ratio might be preferable.

Common issues

While Ford Super Duty axles are generally robust, some common issues can arise:

• Ring & Pinion Whine: A persistent whining noise that changes with vehicle speed or acceleration/deceleration can indicate worn or improperly set up ring and pinion gears. This often requires professional diagnosis and repair, including new gears and a proper setup.

• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Worn carrier bearings can lead to humming, rumbling, or grinding noises, especially when turning. If left unaddressed, it can cause more severe damage to the differential.

• Limited-Slip Clutch Wear: For trucks equipped with a limited-slip differential (LSD), the internal clutch packs can wear out over time. Symptoms might include a chattering or popping noise from the rear end when turning, especially at low speeds. Often, a fluid change with the correct friction modifier can temporarily help, but eventually, the clutch packs may need replacement.

• Axle Seal Leaks: Leaking axle seals are a common issue. These seals prevent gear oil from escaping the axle housing and contaminating the brakes. Leaks should be addressed promptly to prevent low fluid levels and potential damage.

Regular differential fluid changes with the correct type and viscosity of gear oil, along with an appropriate friction modifier for limited-slip units, are key to prolonging the life of your F-250's axle components.

Find a driveline shop on Repairius.